While you can pick up many NES games for next to nothing, there are several cartridges that fetch eye-watering prices these days, especially in good condition. Just last month a mint, unopened copy of the original Super Mario Bros. sold for over $100,000.

That's all well and good, but Super Mario Bros. carts are ten-a-penny; it's the rarities like Stadium Events or the Nintendo World Championships cartridge that really get our juices flowing, and it seems that a copy of the latter has surfaced in the wild.

The cartridge was produced in very limited numbers for finalists of the 1990 Nintendo World Championships in the USA. Two variants exist, gold and grey, and they're among the most sought-after items for video game collectors, occasionally cropping up and commanding impressive prices.

The video below from retro gaming YouTuber Metal Jesus details the latest super rare find:

The gamer in question, Tim, found the game in his attic and contacted Metal Jesus for advice. His brother apparently played in the tournament which explains how it came to be in his possession. Heading to Pink Gorilla Games in Seattle, he got the cartridge authenticated and it appears to be legitimate.

There's still time to raid the piggy bank if you need this unique piece of Nintendo history in your life. You'll need one hell of a piggy bank, though - according to the video, Tim has already had an offer of $23,000 for the cart.

If you'll excuse us, we're off to double and triple check that none of our siblings played in the Nintendo World Championships before casually tossing their prize in the loft for 29 years.

Have you ever come across something like this in the wild? Do you have any rarities in your game collection? Let us know in the comments.